Kensaku Mori, Daisuke Deguchi, Jun Sugiyama, Yasuhito Suenaga, Junichiro Toriwaki, C. R. Maurer, Jr., Hitotugu Takabatake, and Hiroshi Natori : A method for camera motion tracking of a bronchoscope using epipolar geometry analysis and intensity image registration of real and viutrual endoscopic images